David Clayton-Thomas dies at 84 at St. Michael’s Hospital in Toronto, his publicist Eric Alper says and no cause is disclosed.Clayton-Thomas joined Blood, Sweat & Tears in 1968, replacing Al Kooper on a recommendation from Judy Collins and helping the band win two Grammys and chart three major singles.The group played Woodstock in 1969 and toured Eastern Europe on a US State Department-sponsored trip during which Clayton-Thomas and other members criticized Communist regimes.Steve Katz and other colleagues say Clayton-Thomas' husky tenor reshaped the band's brass-rock sound, he left in 1972 and his solo work spans more than a dozen albums.